From 16094a3633ce22ff4861d6381dd804538bcd25c5 Mon Sep 17 00:00:00 2001
From: Matthew Dillon <dillon@apollo.backplane.com>
Date: Sun, 16 Aug 2009 21:03:08 -0700
Subject: [PATCH] AMD64 - Fix bogus signal interruption

* The TF_XFLAGS field in the trap frame was not getting cleared on trap and
  syscall entry.  This field can cause a mailbox signal to be flagged in
  the signal frame which in turn can cause the next blockable system call
  to return EINTR.

  This fixes the last issue with mount_mfs.

* Cast the signal function to intptr_t rather then int.
---
 sys/kern/kern_sig.c                 |    6 +++---
 sys/platform/pc64/amd64/exception.S |    6 ++++++
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c
index c8030e7..d5fc263 100644
--- a/sys/kern/kern_sig.c
+++ b/sys/kern/kern_sig.c
@@ -1677,8 +1677,8 @@ issignal(struct lwp *lp, int maytrace)
 		 * Return the signal's number, or fall through
 		 * to clear it from the pending mask.
 		 */
-		switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
-		case (int)SIG_DFL:
+		switch ((intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) {
+		case (intptr_t)SIG_DFL:
 			/*
 			 * Don't take default actions on system processes.
 			 */
@@ -1731,7 +1731,7 @@ issignal(struct lwp *lp, int maytrace)
 
 			/*NOTREACHED*/
 
-		case (int)SIG_IGN:
+		case (intptr_t)SIG_IGN:
 			/*
 			 * Masking above should prevent us ever trying
 			 * to take action on an ignored signal other
diff --git a/sys/platform/pc64/amd64/exception.S b/sys/platform/pc64/amd64/exception.S
index a925abe..a0c8c93 100644
--- a/sys/platform/pc64/amd64/exception.S
+++ b/sys/platform/pc64/amd64/exception.S
@@ -128,6 +128,7 @@ IDTVEC(xmm)
 	subq $TF_ERR,%rsp; \
 	movq $(a),TF_TRAPNO(%rsp) ; \
 	movq $0,TF_ADDR(%rsp) ; \
+	movq $0,TF_XFLAGS(%rsp) ; \
 	jmp alltraps
 IDTVEC(tss)
 	TRAP_ERR(T_TSSFLT)
@@ -200,6 +201,7 @@ IDTVEC(dblfault)
 	movq	$T_DOUBLEFLT,TF_TRAPNO(%rsp)
 	movq	$0,TF_ADDR(%rsp)
 	movq	$0,TF_ERR(%rsp)
+	movq	$0,TF_XFLAGS(%rsp)
 	movq	%rdi,TF_RDI(%rsp)
 	movq	%rsi,TF_RSI(%rsp)
 	movq	%rdx,TF_RDX(%rsp)
@@ -233,6 +235,7 @@ IDTVEC(page)
 	movq	%rdi,TF_RDI(%rsp)	/* free up a GP register */
 	movq	%cr2,%rdi		/* preserve %cr2 before ..  */
 	movq	%rdi,TF_ADDR(%rsp)	/* enabling interrupts. */
+	movq	$0,TF_XFLAGS(%rsp)
 	testq	$PSL_I,TF_RFLAGS(%rsp)
 	jz	alltraps_pushregs_no_rdi
 	sti
@@ -248,6 +251,7 @@ IDTVEC(prot)
 	subq	$TF_ERR,%rsp
 	movq	$T_PROTFLT,TF_TRAPNO(%rsp)
 	movq	$0,TF_ADDR(%rsp)
+	movq	$0,TF_XFLAGS(%rsp)
 	movq	%rdi,TF_RDI(%rsp)	/* free up a GP register */
 	leaq	doreti_iret(%rip),%rdi
 	cmpq	%rdi,TF_RIP(%rsp)
@@ -283,6 +287,7 @@ IDTVEC(fast_syscall)
 	movq	$KUDSEL,TF_SS(%rsp)
 	movq	$KUCSEL,TF_CS(%rsp)
 	movq	$2,TF_ERR(%rsp)
+	movq	$0,TF_XFLAGS(%rsp)	/* note: used in signal frame */
 	movq	%rdi,TF_RDI(%rsp)	/* arg 1 */
 	movq	%rsi,TF_RSI(%rsp)	/* arg 2 */
 	movq	%rdx,TF_RDX(%rsp)	/* arg 3 */
@@ -337,6 +342,7 @@ IDTVEC(nmi)
 	movq	$(T_NMI),TF_TRAPNO(%rsp)
 	movq	$0,TF_ADDR(%rsp)
 	movq	$0,TF_ERR(%rsp)
+	movq	$0,TF_XFLAGS(%rsp)
 	movq	%rdi,TF_RDI(%rsp)
 	movq	%rsi,TF_RSI(%rsp)
 	movq	%rdx,TF_RDX(%rsp)
-- 
1.7.7.2